1. Brief Description of the Prior Art
Automatic welding systems for effecting an annular weld about the exterior or interior of pipes or tubes being butt welded together are known. Typically, such welding systems include means for effecting annular travel of the welding torch head about the exterior or interior of the junction of the pipes to be joined.
Amongst the systems which have been proven to obtain the above objectives are the systems illustrated and described in U.S. Pat. No. 3,873,798 to Friedman et al; U.S. Pat. No. 4,344,553 to Lesher et al; U.S. Pat. No. 4,372,474 to Taff; and U.S. Pat. No. 4,386,726 to Taff.
With the increased requirement for the use of stainless steel and high alloy pipes, tubes, and fittings, in the medical, pharmaceutical, food processing, beverage, and dairy fields, welding systems capable of providing an inert atmosphere or non oxidizing atmospheres adjacent the welding zone were required.
2. Summary of the Invention
With the aforementioned considerations, the present invention has as an object to produce an improved tool for aligning and holding two pipes in butting relationship preparatory to welding and providing an inert atmosphere adjacent the welding zone.
Another object of the invention is to produce an expandable tool for aligning and holding pipes during welding thereof.
Another object of the invention is to produce an expandable tool for aligning and holding pipes and providing an inert atmosphere adjacent the welding zone.
Another object of the invention is to produce an improved tool for aligning and holding pipes during the welding thereof and providing an inert gas environment adjacent the welding zone and militating against the escape of the gas from the zone.
Another object of the invention is to produce an improved tool for aligning and holding pipes during the welding thereof which is capable of introducing an inert gas to the welding zone to prevent the oxidation of elements such as chromium in the base material.
Another object of the invention is to produce an improved tool for aligning and holding pipes during the welding thereof and is capable of efficiently directing and concentrating inert gas adjacent the weld zone.
Still another object of the invention is to produce an improved tool for aligning and holding pipes during the welding thereof which is simple in structure and will reduce the normal setup and alignment time and increase the attendant production.
Another object of the invention is to produce an improved tool for aligning and holding pipes during the welding thereof and simultaneously is capable of directing an inert purge gas to efficiently flood the zone adjacent the weld during the welding operation.
The above as well as other objectives of the invention are achieved by an expandable tool including an annular array of radially movable gripping members for engagement with and alignment of pipes to be welded wherein the gripping members cooperate to define a predetermined zone adjacent the inner surfaces of the ends of the pipes to be welded through appropriately formed passageways which establish communication with a source of inert gas and the predetermined zone adjacent the weld to be formed.